Essential Variables to Consider for Successful Brook Charr Reintroduction: A Case Study at La Mauricie National Park

This study was a unique opportunity to test a protocol of reintroduction to restore an indigenous brook charr population in its original habitat at La Mauricie National Park (Québec, Canada). Our approach included a breeding plan that ensured a minimum effective population size, transferring the existing standing genetic variation, and subtle “pelagic-littoral resource polymorphism” from a neighbouring wild population to the newly founded population. Approximately 30,000 young-of-the-year were released in the lake over a two-year period, and 1,000 F1 and 1,000 F2 offspring were genotyped at 15 microsatellite loci. Our results suggest that the genetic diversity in the source population was transferred and maintained in the newly founded population, and that the effective population size was comparable to that of the source one. Results of parentage assignment show that the relative survival of families is high between the two first age classes (0+ and 1+). Discriminant function analyses suggest that morphological differences were present between individuals captured in the littoral and pelagic zones. However, stomach contents did not differ between individuals sampled in both zones of the lake, suggesting a high phenotypic plasticity in the feeding habits of expanding populations. The impacts of this management plan will be discussed.